In computer stream processing, a stream may be viewed as a relation or table that changes over time. Each entry in the stream may include a payload and potentially a timestamp. The timestamp indicates a time at which the entry occurred, although the time may have no bearing on a time in the real world. The timestamp may simply indicate a value by which an entry may be ordered relative to other entries in the stream. The payload may include one or more fields that include data associated with the entry.
Many real-world examples of streams exist. For example, a computer monitoring system may generate a stream of events that relate to the health of a computer system. As another example, the Web sites accessed by Internet users may be represented as a stream of events. Extracting and using the information contained in streams is challenging.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.